U.S. patent number 7,600,983 [Application Number 11/270,485] was granted by the patent office on 2009-10-13 for radial plunger pump and method for manufacturing pump housing.
This patent grant is currently assigned to Advics Co., Ltd.. Invention is credited to Masahiko Abe, Kenichi Suzuki, Yutaka Yamashita.
United States Patent |
7,600,983 |
Yamashita , et al. |
October 13, 2009 |
Radial plunger pump and method for manufacturing pump housing
Abstract
A pump housing supporting a driving shaft has a plurality of
cylinder bores extending radially and arranged at substantially
regular intervals around an outer periphery of the driving shaft.
Each cylinder bore has a plunger fitted therein, which reciprocates
in response to a rotation of the driving shaft. An inlet, an inlet
valve, an outlet, and an outlet valve are provided for each
plunger. Fluid flowing from an inlet port provided in the pump
housing flows into each inlet, and moreover, fluid flowing from
each outlet passes through an outlet passage and flows into an
outlet port provided in the pump housing. The outlet passage has a
plurality of communication holes corresponding to the outlet
valves. Outlet ends of the communication holes converge on one spot
in the pump housing.
Inventors: |
Yamashita; Yutaka (Anjo,
JP), Suzuki; Kenichi (Nishikamo-gun, JP),
Abe; Masahiko (Chiryu, JP) |
Assignee: |
Advics Co., Ltd. (Kariya,
Aichi-Pref., JP)
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Family
ID: |
36386516 |
Appl.
No.: |
11/270,485 |
Filed: |
November 10, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060104828 A1 |
May 18, 2006 |
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Foreign Application Priority Data
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Nov 16, 2004 [JP] |
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2004-332329 |
Sep 27, 2005 [JP] |
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2005-280231 |
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Current U.S.
Class: |
417/273;
29/888.02; 417/570 |
Current CPC
Class: |
B60T
8/368 (20130101); B60T 8/4031 (20130101); F04B
1/053 (20130101); F04B 53/16 (20130101); F04B
1/0404 (20130101); Y10T 29/49236 (20150115) |
Current International
Class: |
F04B
1/04 (20060101); F04B 27/04 (20060101) |
Field of
Search: |
;417/273,570,269,423.14
;123/206,495,179.17 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2001-500593 |
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Jan 2001 |
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JP |
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WO 2004033905 |
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Apr 2004 |
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WO |
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Primary Examiner: Kramer; Devon C
Assistant Examiner: Bayou; Amene S
Attorney, Agent or Firm: Buchanan Ingersoll & Rooney
PC
Claims
What is claimed is:
1. A radial plunger pump comprising: a pump housing rotatably
supporting a driving shaft and having a plurality of cylinder bores
extending radially and arranged at substantially regular intervals
around an outer periphery of the driving shaft, an inlet port
sucking in fluid, and an outlet port discharging fluid; a plunger
fitted in each cylinder bore to form a pump chamber and
reciprocating in response to a rotation of the driving shaft; an
inlet passage through which the inlet port communicates with the
pump chamber; an outlet passage through which the pump chamber
communicates with the outlet port; an inlet valve provided for each
plunger which establishes and cuts off a communication between the
inlet passage and the pump chamber in response to reciprocating
motion of the plunger; and an outlet valve provided for each
plunger which establishes and cuts off a communication between the
pump chamber and the outlet passage in response to the
reciprocating motion of the plunger, wherein the outlet passage has
a plurality of outlet chambers each of which is formed by an
attachment hole extending radially and accommodating each plunger,
and each of which communicates with each pump chamber via each
outlet valve, and wherein the outlet passage has a plurality of
communication holes each of which extends from an inner side
surface of each attachment hole in a direction that is not
perpendicular to an axis line of the driving shaft, and outlet ends
of the communication holes converge on one spot in the pump
housing.
2. The radial plunger pump according to claim 1, wherein the pump
housing has an accumulator attachment hole communicating with the
outlet port, and wherein the converging spot of the outlet ends of
the communication holes is disposed in a connection hole connected
to the accumulator attachment hole.
3. The radial plunger pump according to claim 1, wherein the
communication holes are given substantially the same length.
4. The radial plunger pump according to claim 2, wherein the
plungers comprise at least three plungers, wherein the accumulator
attachment hole disposed in the pump housing and communicating with
the outlet port intersects with an axis line of the driving shaft,
wherein the communication hole disposed closest to the accumulator
attachment hole has a length greater than those of the remaining
communication holes, and wherein the converging spot of the
communication holes is positionally shifted from a shaft axis of
the driving shaft in a radial direction thereof.
5. The radial plunger pump according to claim 1, wherein the
direction is not perpendicular to a straight line that passes
through the one spot and is parallel to the axis line of the
driving shaft.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to radial plunger pumps, and
particularly, to a radial plunger pump having a plurality of
plungers arranged at substantially regular intervals around an
outer periphery of a driving shaft, and to a method for
manufacturing a pump housing.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2001-500593 discloses an
example of a radial plunger pump of the above-mentioned type, in
which a pump housing is provided for supporting a driving shaft in
a rotatable manner. The pump housing has a plurality of cylinder
bores extending radially and arranged at substantially regular
intervals around the outer periphery of the driving shaft. Each
cylinder bore has a plunger fitted therein, which reciprocates in
response to the rotation of the driving shaft.
In the above-described plunger pump, an inlet, an inlet valve, an
outlet, and an outlet valve are provided for each plunger. Fluid
flowing from an inlet port provided in the pump housing passes
through an inlet passage and flows into each inlet. Moreover, fluid
flowing from each outlet passes through an outlet passage and flows
into an outlet port provided in the pump housing.
According to such a conventional radial plunger pump described
above, the outlet passage has a plurality of communication holes
corresponding to the outlet valves. Outlet ends of the
communication holes are connected to different sections of the
outlet port. For this reason, the conventional radial plunger pump
has a plurality of connecting sections between the communication
holes and the outlet port. In other words, the radial plunger pump
has a plurality of sections where burrs are formed. This means that
a burr-removal process is necessary for each of the connecting
sections between the communication holes and the outlet port, which
is problematic in view of work efficiency and reliability.
SUMMARY OF THE INVENTION
In order to solve the problem mentioned above, the present
invention provides a radial plunger pump including a pump housing
rotatably supporting a driving shaft. The pump housing has a
plurality of cylinder bores extending radially and arranged at
substantially regular intervals around an outer periphery of the
driving shaft. Each cylinder bore has a plunger fitted therein, the
plunger reciprocating in response to a rotation of the driving
shaft. An inlet, an inlet valve, an outlet, and an outlet valve are
provided for each plunger. Fluid flowing from an inlet port
provided in the pump housing passes through an inlet passage and
flows into each inlet. Fluid flowing from each outlet passes
through an outlet passage and flows into an outlet port provided in
the pump housing. The outlet passage has a plurality of
communication holes corresponding to the outlet valves. Outlet ends
of the communication holes converge on one spot in the pump
housing. Furthermore, the converging spot of the outlet ends of the
communication holes may be disposed in a connection hole connected
to an accumulator attachment hole, which is disposed in the pump
housing and communicates with the outlet port.
According to the radial plunger pump of the present invention, the
outlet passage has the plurality of communication holes
corresponding to the outlet valves, and moreover, the outlet ends
of the communication holes converge on one spot in the pump
housing. Accordingly, since the outlet ends of the communication
holes are joined at one spot, only one section where burrs are
formed is present, thereby achieving better work efficiency for
removing burrs and higher reliability. In a case where the
converging spot of the outlet ends of the communication holes is
disposed in the connection hole connected to the accumulator
attachment hole communicating with the outlet port, the converging
spot of the communication holes may also be joined to the
accumulator attachment hole.
Furthermore, according to the present invention, the communication
holes may be given substantially the same length. In this case, the
communication holes can be formed at the same angle with respect to
the shaft axis of the driving shaft. Accordingly, when the
plurality of communication holes is to be formed in the pump
housing using a single hole-forming device, the pump housing is
rotated around the shaft axis of the driving shaft by predetermined
intervals without changing the fixed angle of the hole-forming
device with respect to the shaft axis of the driving shaft. In a
state where the pump housing is fixed in position at each interval,
the hole-forming process using the hole-forming device is performed
(the hole-forming device is moved at the fixed angle). By repeating
the hole-forming process at the predetermined intervals, the
communication holes are formed sequentially in the pump housing. In
this case, the processing direction using the hole-forming device
and the processing angle are kept constant so that the plurality of
communication holes can be formed equiangularly in the pump housing
with respect to the shaft axis of the driving shaft. Furthermore,
in this case, the discharge resistance can be made substantially
the same, thereby stabilizing the discharging pulses.
Furthermore, according to the present invention, the plungers may
include at least three plungers. Moreover, the accumulator
attachment hole disposed in the pump housing and communicating with
the outlet port may intersect with (e.g. perpendicular to) an axis
line of the driving shaft. The communication hole disposed closest
to the accumulator attachment hole may have a length greater than
those of the remaining communication holes. The converging spot of
the communication holes may be positionally shifted from a shaft
axis of the driving shaft in a radial direction thereof (or in
other words, shifted away from an accumulator fitted in the
accumulator attachment hole). In this case, the longest
communication hole can be inclined closer to an end of the driving
shaft, thereby preventing an interference between the communication
hole and the accumulator attachment hole and also contributing to
size reduction of the pump housing in the axial direction of the
driving shaft.
Furthermore, the present invention also provides a method for
manufacturing a pump housing including at least three pumps
centered on a driving shaft and extending radially therefrom, at
least three pumps having outlets disposed at an equal distance from
the driving shaft; and communication holes extending from the
corresponding outlets to an accumulator and arranged at an equal
angle with respect to the driving shaft. The method includes the
step of repetitively rotating the pump housing around the driving
shaft and moving a hole-forming device from the outlets at the
equal angle with respect to the driving shaft so as to form the
communication holes.
In this method for manufacturing a pump housing, when the plurality
of communication holes is to be formed in the pump housing using a
single hole-forming device, the hole processing can be achieved
without changing the fixed angle of the hole-forming device with
respect to the shaft axis of the driving shaft. Accordingly, the
pump housing can be manufactured readily.
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features and many of the attendant
advantages of the present invention will be readily appreciated as
the same becomes better understood by reference to the following
detailed description of the preferred embodiments when considered
in connection with the accompanying drawings, in which:
FIG. 1 is a vertical sectional view of a radial plunger pump
according to a first embodiment of the present invention;
FIG. 2 is a cross-sectional view of the radial plunger pump taken
along line 2-2 in FIG. 1;
FIG. 3 is a cross-sectional view illustrating a relationship among
communication holes, a connection hole, an accumulator attachment
hole, and an outlet port included in a pump housing shown in FIG.
1;
FIG. 4 is a vertical sectional view of a radial plunger pump
according to a second embodiment of the present invention; and
FIG. 5 is a cross-sectional view illustrating a relationship among
communication holes, a connection hole, an accumulator attachment
hole, and an outlet port included in a pump housing shown in FIG.
4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described with reference to the
drawings. FIGS. 1 to 3 illustrate a radial plunger pump according
to a first embodiment. The radial plunger pump according to the
first embodiment includes a driving shaft 11 rotated by an output
shaft Ma of an electric motor M, and a pump housing 13 rotatably
supporting the driving shaft 11. The pump housing 13 has three
cylinders 15 and three plungers 17 fitted therein. The electric
motor M is attached to the pump housing 13.
The driving shaft 11 is fitted in a shaft attachment hole 13a of
the pump housing 13 via a pair of ball bearings 21, 21 and a seal
ring 23. The central portion of the driving shaft 11 is provided
with an eccentric shaft component 11a. The eccentric shaft
component 11a moves eccentrically in response to the rotation of
the driving shaft 11 around the shaft axis thereof. A driving ring
27 is rotatably fitted around the outer periphery of the eccentric
shaft component 11a via a needle bearing 25.
Referring to FIG. 2, the pump housing 13 has a plurality of
cylinder attachment holes 13b arranged radially at substantially
regular intervals in the circumferential direction of the eccentric
shaft component 11a of the driving shaft 11. Inner ends of the
cylinder attachment holes 13b communicate with the shaft attachment
hole 13a. Moreover, the pump housing 13 also has an inlet port 13c
extending radially without overlapping the cylinder attachment
holes 13b. An inner end of the inlet port 13c communicates with the
shaft attachment hole 13a.
Furthermore, referring to FIGS. 1 and 3, the pump housing 13 has an
outlet port 13d and an accumulator attachment hole 13e disposed
substantially perpendicular to each other. An accumulator 29 is
fitted in the accumulator attachment hole 13e in a fluid-tight
manner via a seal ring 28. Furthermore, the pump housing 13 has
three communication holes 13f and one connection hole 13g via which
outer end portions of the cylinder attachment holes 13b and an
inner end of the accumulator attachment hole 13e communicate. The
pump housing 13 also has a drain port 13h for drainage.
Each communication hole 13f is formed by drilling a hole inward at
an angle from the outer end of the corresponding cylinder
attachment hole 13b by using a hole-forming device, such that one
end of the communication hole 13f positioned at a predetermined
distance from the shaft axis (center of rotation) of the driving
shaft 11 communicates with the corresponding cylinder attachment
hole 13b, while the other end (i.e. an outlet end) communicates
with the connection hole 13g. Moreover, the ends of the
communication holes 13f that communicate with the connection hole
13g converge on one spot inside the pump housing 13 (i.e. a spot
positioned on an extension of the shaft axis of the driving shaft
11). The communication holes 13f have substantially the same
length. On the other hand, the connection hole 13g is formed by
drilling a hole coaxially with the accumulator attachment hole 13e
by using a hole-forming device. The accumulator attachment hole 13e
communicates with the outlet port 13d and extends substantially
perpendicular to the axis line of the driving shaft 11.
The cylinders 15 are fitted in the cylinder attachment holes 13b of
the pump housing 13 in a fluid-tight, immovable manner via seal
rings 14. The cylinders 15 extend radially around the outer
periphery of the driving shaft 11. Each cylinder 15 forms a pump
chamber R1 together with the corresponding plunger 17. Moreover,
each cylinder 15 is provided with an outlet 15a and an outlet valve
31, such that a fluid (hydraulic fluid) discharged from the pump
chamber R1 and passing through the outlet 15a and the outlet valve
31 flows into an outlet chamber R2 defined by the pump housing 13
and a cap 33.
The fluid flowing into each outlet chamber R2 travels through an
outlet passage defined by the corresponding communication hole 13f
and the connection hole 13g and also through an outlet check valve
35 attached to the outlet end of the connection hole 13g. As a
result, the fluid flows into the accumulator attachment hole 13e
and also into the outlet port 13d via the accumulator attachment
hole 13e.
The plungers 17 are fitted in cylinder bores 15b of the cylinders
15 in a fluid-tight manner via seal rings 18, and are also movable
in the axial direction of the cylinders 15. Each plunger 17 and the
corresponding cylinder 15 have a spring 37 disposed therebetween,
such that the spring 37 biases the plunger 17 radially towards the
driving shaft 11. An inner end of the plunger 17 is engaged to an
outer periphery of the driving ring 27. Accordingly, the eccentric
shaft component 11a of the driving shaft 11 and the springs 37
operate in cooperation with each other so as to reciprocate the
plungers 17 axially within the cylinders 15 in response to the
rotation of the driving shaft 11, thereby increasing and decreasing
the volume of the pump chambers R1.
Each plunger 17 is provided with an inlet 17a, an inlet passage
17b, and an inlet valve 39. The fluid from the inlet port 13c flows
into the shaft attachment hole 13a also serving as an inlet
passage, and is introduced into the pump chambers R1 via the inlets
17a, the inlet passages 17b, and the inlet valves 39.
In the radial plunger pump according to the first embodiment, when
the driving shaft 11 is rotated by the output shaft Ma of the
electric motor M, the eccentric shaft component 11a of the driving
shaft 11 and the springs 37 operate in cooperation with each other
so as to reciprocate the plungers 17 axially within the cylinders
15 in response to the rotation of the driving shaft 11.
Consequently, the volume of the pump chambers R1 is increased and
decreased, whereby the fluid sucked into the inlet port 13c is
discharged to the accumulator attachment hole 13e and the outlet
port 13d.
On the other hand, in the radial plunger pump according to the
first embodiment, the outlet ends of the communication holes 13f
provided in the pump housing 13 converge on one spot inside the
pump housing 13. Accordingly, since the outlet ends of the
communication holes 13f are joined at one spot, only one section
where burrs are formed is present, thereby achieving better work
efficiency for removing burrs and higher reliability.
Furthermore, in the radial plunger pump according to the first
embodiment, the communication holes 13f are given substantially the
same length, and the outlet ends of the communication holes 13f are
joined at a spot positioned on the extension of the shaft axis of
the driving shaft 11. Thus, the communication holes 13f are formed
at the same angle (i.e. an angle formed with respect to the shaft
axis of the driving shaft 11 by using a hole-forming device). When
the plurality of communication holes 13f is to be formed in the
pump housing 13 using a single hole-forming device (a hole-forming
drill, not shown), the pump housing 13 is rotated around the shaft
axis of the driving shaft 11 by predetermined intervals
(120.degree.) without changing the fixed angle .theta. (see FIG. 1)
of the hole-forming device with respect to the shaft axis of the
driving shaft 11. In a state where the pump housing 13 is fixed in
position at each interval, the hole-forming process using the
hole-forming device is performed (the hole-forming device is moved
at the fixed angle .theta.). By repeating the hole-forming process
at the predetermined intervals, the communication holes 13f are
formed sequentially in the pump housing 13. In this case, the
processing direction (the direction indicated by an arrow in FIG.
1) using the hole-forming device and the processing angle .theta.
are kept constant so that the plurality of communication holes 13f
can be formed equiangularly in the pump housing 13 with respect to
the shaft axis of the driving shaft 11. Furthermore, in this case,
the discharge resistance can be made substantially the same,
thereby stabilizing the discharging pulses.
According to the first embodiment, as shown in FIGS. 1 and 3, the
communication holes 13f are given substantially the same length,
and the outlet ends of the communication holes 13f are joined at a
spot positioned on the extension of the shaft axis of the driving
shaft 11. Alternatively, according to a second embodiment shown in
FIGS. 4 and 5, the communication hole 13f closest to the
accumulator attachment hole 13e may be given a length that is
greater than those of the remaining communication holes 13f, such
that the converging spot of the communication holes 13f is shifted
from the shaft axis of the driving shaft 11 in the radial direction
thereof (or in other words, shifted away from the accumulator 29
fitted in the accumulator attachment hole 13e).
In that case, the longest communication hole 13f can be inclined
closer to an end of the driving shaft 11 (right end in FIG. 4),
thereby preventing an interference (communication) between the
communication hole 13f and the accumulator attachment hole 13e and
also contributing to size reduction of the pump housing 13 in the
axial direction of the driving shaft 11. In this case, the pump end
of the longest communication hole 13f (left end in FIG. 4) may be
shifted outward (upward in FIG. 4) so as to achieve further size
reduction.
Although the above-described embodiments are directed to a radial
plunger pump equipped with three plungers 17 and attachments
thereof, the number of the plungers 17 and the attachments thereof
is not limited to three as in the above-described embodiments as
long as the number is more than one. Furthermore, although the
plungers 17 are fitted in the cylinder bores 15b of the
corresponding cylinders 15 included in the pump housing 13, the
plungers 17 may alternatively be fitted in cylinder bores provided
directly in the pump housing 13.
* * * * *